The way to view historical alarms would be via the transactionlog.db located inside your NAS folder on you main NAS.

You can also view then via DB:

NAS_ALARMS table contains all alarms from all probes. Anything that appears in the alarm console could be considered an active alarm. (The alarm console is essentially displaying the output of 'select * from NAS_ALARMS').

When an alarm is acknowledged, it's deleted from the NAS_ALARMS table. If you need to drill into historical records, or see recent alarms that have been cleared, then you'll need to query into the NAS_TRANSACTION_LOG and/or NAS_TRANSACTION_SUMMARY tables.

Also please note that the DB will only have historical alarms to the period you set for data retention.